From cdshaw@umbilicus.artsci.washington.edu Thu May 28 13:41:47 1998 Received: from burdell.cc.gatech.edu (root@burdell.cc.gatech.edu [130.207.3.207]) by lennon.cc.gatech.edu (8.8.4/8.6.9) with ESMTP id NAA10913 for ; Thu, 28 May 1998 13:41:43 -0400 (EDT) Received: from wheaten.hitl.washington.edu (dow1bpbXeJIeIuBjZOmWLYkWDzjegciH@[128.95.73.60]) by burdell.cc.gatech.edu (8.8.4/8.6.9) with ESMTP id NAA16932 for ; Thu, 28 May 1998 13:41:41 -0400 (EDT) Received: from umbilicus.artsci.washington.edu (umbilicus.artsci.washington.edu [128.95.248.206]) by wheaten.hitl.washington.edu (8.8.8/8.6.12) with SMTP id KAA21180 for <3d-ui@hitl.washington.edu>; Thu, 28 May 1998 10:41:33 -0700 (PDT) Received: (from cdshaw@localhost) by umbilicus.artsci.washington.edu (950413.SGI.8.6.12/8.6.10) id KAA14885 for 3d-ui@hitl.washington.edu; Thu, 28 May 1998 10:41:33 -0700 From: Chris Shaw Message-Id: <199805281741.KAA14885@umbilicus.artsci.washington.edu> Subject: Pointers To: 3d-ui@hitl.washington.edu Date: Thu, 28 May 1998 10:41:33 -0700 (PDT) In-Reply-To: <356CDDFC.B6673B4C@mic.atr.co.jp> from "Ivan Poupyrev" at May 27, 98 08:46:04 pm Reply-To: cdshaw@cs.URegina.ca X-Mailer: ELM [version 2.4 PL25] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Status: RO Ivan, > Resulted "super" > image plane will be not a plane but some sort of sphere with the user > in the middle and objects around projected on this sphere. The user is not a point. Is the user the user's eye? The user's two eyes? I think I've read in Jeff's paper(s) that stereo makes crushing-your-head more complicated. > From this > point of view the task of selecting objects using image plane technique > becomes essentially 2D, since manipulating distance to the object is > not needed, only direction to the object is important. That is, you just have to identify a point on this sphere. > It can be > argued that all pointing techniques are essentially 2D techniques from > the user-centered perspective and I have some experimental data to > support this claim. Barring gross misinterpretation on my part, here's a refutation: The spotlight/flashlight technique in JDCAD, THRED, and SFA is a "6" DOF technique. You can reach around the side of an object and illuminate (pick) objects from the side. For example, you can lie on top of the bed, reach down with the spotlight and point under the bed to find the cat. I say "6" DOF because one degree of orientation freedom isn't really useful. If you rotate about the axis of the beam of light, it doesn't change what is pick-able. This does not necessarily make it a great technique. -- Chris Shaw University of Regina cdshaw@cs.URegina.ca Assistant Professor http://www.cs.uregina.ca/~cdshaw